Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plans (Narrative) (Details)

v2.4.0.6
Stock Incentive Plans (Narrative) (Details) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Length of time options exercisable, years 10 years    
Shares available for future awards 2,284,953    
Stock compensation expense $ 25,332,000 $ 18,171,000 $ 13,874,000
Income tax benefit recognized 8,952,000 5,804,000 4,713,000
Fair value of restricted stock and restricted stock units 38,576,000 22,280,000 13,012,000
Unrecognized compensation cost related to non-vested share 67,834,000    
Weighted-average period 1 year 8 months 12 days    
Actual tax benefit realized $ 1,078,000 $ 955,000 $ 883,000
Employee stock purchase plan issued 47,613 34,966 37,048
Stock Options [Member] | Minimum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years 3 years    
Stock Options [Member] | Maximum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years 5 years    
Restricted Stock Units Awards [Member] | Minimum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years 1 year    
Restricted Stock Units Awards [Member] | Maximum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years 10 years